From Windows 7 onward, OEM licenses for Windows are locked to a specific motherboard. When that copy of Windows is activated, it will report its serial number and information from the motherboard's BIOS (or UEFI for more recent motherboards) to Microsoft. If the motherboard information changes, Microsoft assumes the copy of Windows is pirated and eventually turns off features remotely. OEM licenses are not transferable between hardware configurations; retail licenses are. Previously unused OEM licenses can be purchased on NewEgg and TigerDirect; they're usually 10 percent less expensive than the comparable retail version.

1. Connect your optical drive to your computer. Your computer may already have an optical drive installed, but many refurbished business laptops or contract-built desktop computers do not.

2. Hold down the key combination specified by your motherboard manufacturer to access the BIOS of your computer.

3. Set the BIOS to check for an optical drive as the boot volume. This will usually be under "Boot Order" or something similar in the BIOS.

4. Insert the Windows OEM installation disc into the drive. When prompted, enter the serial number provided with your OEM license.

5. Reboot the machine. The Windows Installer runs and configures your OEM copy of Windows for this machine. The Windows Installer automatically detects the hardware on the computer. All you should have to do is specify the name and password of an Administrator account and a user-level account.

6. Activate Windows by going online; the first time you connect to the Internet, Windows will attempt to connect to the Microsoft authentication servers. This will usually be the first thing that happens after a successful installation.

Things Needed

Optical drive

Previously uninstalled OEM license

Tips

While not guaranteed to work, it is sometimes possible to reinstall an OEM license for Windows 7 or Windows 8 on a new computer. The trick is that the motherboard must be identical (including BIOS versions) to the motherboard of the old computer and must have been manufactured at about the same time. Depending on how your business purchases computer hardware, you may have enough parts from old machines that you can assemble a new computer with a motherboard that matches that of the computer you're replacing.

If you want a transferable Windows license, buy the retail version. The money you save on the OEM version is still less than the cost of buying a new copy of Windows when you retire an existing computer.

About the Author

Ken Burnside has been writing freelance since 1990, contributing to publications as diverse as "Pyramid" and "Training & Simulations Journal." A Microsoft MVP in Excel, he holds a Bachelor of Arts in English from the University of Alaska. He won the Origins Award for Attack Vector: Tactical, a board game about space combat.